Caterpillars may not understand the word “please,” but they still know how to mind their manners. Scientists at Carleton University have just published a paper on insect communication that explains how certain types of caterpillars drag their back ends along leaves to warn intruders of their presence. The dragging motion produces a scraping sound and appears to have evolved over time from walking. Biologist Jayne Yack and her colleagues studied the genes of more than 30 caterpillar species and found that “scraper” species recently evolved an oar-like appendage that creates the warning vibrations. This discovery provides more persuasive evidence that communication signals arise from the repetition and exaggeration of routine behaviors.
However it developed, this signaling is beneficial. Caterpillars who use anal-dragging are able to settle disputes with intruders peacefully and avoid injuries. Sometimes it really does help to talk things out.
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